Thanks for the kind words.
You have my permission to include the Farseer Physics Engine logo in your game. You can use the logo from the project frontpage.

As for the game; It looks like a fun game, but also hard. It looks like the bad guys have the advantage all the time. :)
You could include puzzels where the player ball needs to complete some kind of task before proceeding, but the enemies would make it really hard to complete the task. To help the player, he could gather powerups, like stealth (disguise perhaps - look like one
of the enemies), weapons and the like.

It's interesting you mentioned the stealth aspect, this is something I've actually already implemented (it was not finished by the time the video was captured). Basically, there are a couple of levels that are stacked with so many enemies the only way to
get through (for the most part) is by disguise... so you don an outfit that makes you look like one of them. I'll show it off in the next preview. But I'm glad you suggested it :)

As for powerups, I haven't really come up with any compelling ones, besides the usual temporary-kill-everything-you-touch-potion/item. Once I've completed the version for playtest, I'll (hopefully) find out if the game is too hard w/o more powerups. Hopefully
my level design skillz will be good enough to make it manageable, though.